Hello!
Regarding your second question, please see http://www.spchart.com/demo/helpdesk-dashboard. The first chart on that page is exactly about that. Check the Configuration link for information about how to build it. Note that the control you’ll have to insert yourself, to see how check my post here [url]Filter Drop Down in Helpdesk Dashboard Demo].
Regarding your first question, my advice would be to replicate first the example I’ve just mentioned and then it will be evident how to do this for two controls (“to” and “from”).